The invention concerns a nuclear reactor installation with a containment and a live-steam line which leads from the inside of the containment to the outside and contains a fast-acting valve with an aperture cross section corresponding to the cross section of the live-steam line and with a valve disk which is closed in case of a leak in the live-steam line, under the action of a pressure medium.
The fast-acting valve permits to shut off the live-steam line quickly, particularly if in the case of a leak the danger exists of steam, which might possibly be radioactively contaminated due to an accident, getting to the outside. However, the closing means of necessity also that the cooling of the reaction installation, i.e., the transport of energy in the form of the steam flow, is interrupted. This gives rise to problems, as it is not always possible, even with a fast shutdown of the nuclear reactor, to lower the production of energy fast enough to keep particularly the pressure within permissible limits in the generation of steam. For these problems, the invention attempts to find a solution in the form of a valve combination which is to serve at the same time as a shut-off valve and a safety valve.